The objectives for renewal are to continue to recall human subjects for the purpose of comparing restorative materials in the oral environment, under controlled operative conditions. This study compares composi resins with silicate and amalgam restorations in all dental classifications, in durability, tendency for recurrent caries, and esthetics. A concurrent long-terms clinical study also assesses the degree of amalgam corrosion (gamma 2) found when placed adjacent to gold casting. Extensive ongoing laboratory experiments with new and with commonly used materials supplement the clinical study. The continuation of primate pulpal response studies are most important, of the many products and techniques which are either under consideration, or are being used clinically.